Target Exam

CUET

Subject

Physics

Chapter

Wave Optics

Question:

Two Polaroids are placed in such a way that their axes make an angle of 60° with each other. If an unpolarized light is incident on a system of these Polaroids, the fraction of transmitted light to the incident light will be

Options:

zero

1/8

3/8

5/8

Correct Answer:

1/8

Explanation:

The correct answer is Option (2) → 1/8

Intensity of unpolarized light after passing through the first Polaroid:

$I_1 = \frac{I_0}{2}$

After passing through the second Polaroid at angle $\theta = 60^\circ$ to the first:

$I_2 = I_1 \cos^2 \theta = \frac{I_0}{2} \cos^2 60^\circ = \frac{I_0}{2} \cdot \left(\frac{1}{2}\right)^2 = \frac{I_0}{8}$

Fraction of transmitted light to incident light: $I_2 / I_0 = 1/8$

Final Answer: $\frac{1}{8}$